Last month, we told you about an exciting new iPhone email client called Mailbox. The app, which has been described as a cross between Clear and Sparrow thanks to its simple, swipe-based UI, is slated to hit the App Store in the next few weeks.

And in anticipation of high demand for the free email client, Mailbox-creator Orchestra opened up a reservation system this morning. It operates on a first-come, first-served basis, and will help the team manage server traffic when the app lands…

Here’s an excerpt from Orchestra’s blog post on why it decided to go with a reservation system:

“In order to ensure that people using Mailbox have a reliable and lightning-fast experience, we’re going to follow the path of services like Gmail, Pinterest, and Spotify and use reservations to control the flow of new accounts. We’ve decided that the best way to do this is with as much transparency as possible, so our system is really simple: reserve your Mailbox today if you haven’t already, and once the app is in the App Store, we will begin filling reservations on a first-come, first-served basis.”

So how do you reserve yourself a free copy of Mailbox? It’s easy. All you have to do is click here to go to the Mailbox registration page. Then you’ll enter in your phone number, and you should receive an SMS with both a Reservation Number and Private Code.

There’s no telling how long you’ll have to wait for the app when it’s released. But once it’s available, you’ll be able to see how many people are still ahead of you in line. You’ll also get an SMS notification when your copy of Mailbox is ready to be downloaded.

The client will be exclusive to the iPhone and Gmail accounts at first, but Orchestra says it has plans to expand in the future. If you haven’t checked it out yet, make sure you watch the video above. It looks like it’s going to change the way many of us handle email.